drivers/platform/x86/lenovo-ymc.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * lenovo-ymc.c - Lenovo Yoga Mode Control driver
   4  *
   5  * Copyright © 2022 Gergo Koteles <soyer@irl.hu>
   6  */
   7
   8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9
  10 #include <linux/acpi.h>
  11 #include <linux/dmi.h>
  12 #include <linux/input.h>
  13 #include <linux/input/sparse-keymap.h>
  14 #include <linux/wmi.h>
  15 #include "ideapad-laptop.h"
  16
  17 #define LENOVO_YMC_EVENT_GUID   "06129D99-6083-4164-81AD-F092F9D773A6"
  18 #define LENOVO_YMC_QUERY_GUID   "09B0EE6E-C3FD-4243-8DA1-7911FF80BB8C"
  19
  20 #define LENOVO_YMC_QUERY_INSTANCE 0
  21 #define LENOVO_YMC_QUERY_METHOD 0x01
  22
  23 static bool force;
  24 module_param(force, bool, 0444);
  25 MODULE_PARM_DESC(force, "Force loading on boards without a convertible DMI chassis-type");
  26
  27 static const struct dmi_system_id allowed_chasis_types_dmi_table[] = {
  28         {
  29                 .matches = {
  30                         DMI_EXACT_MATCH(DMI_CHASSIS_TYPE, "31" /* Convertible */),
  31                 },
  32         },
  33         {
  34                 .matches = {
  35                         DMI_EXACT_MATCH(DMI_CHASSIS_TYPE, "32" /* Detachable */),
  36                 },
  37         },
  38         { }
  39 };
  40
  41 struct lenovo_ymc_private {
  42         struct input_dev *input_dev;
  43 };
  44
  45 static const struct key_entry lenovo_ymc_keymap[] = {
  46         /* Ignore the uninitialized state */
  47         { KE_IGNORE, 0x00 },
  48         /* Laptop */
  49         { KE_SW, 0x01, { .sw = { SW_TABLET_MODE, 0 } } },
  50         /* Tablet */
  51         { KE_SW, 0x02, { .sw = { SW_TABLET_MODE, 1 } } },
  52         /* Drawing Board */
  53         { KE_SW, 0x03, { .sw = { SW_TABLET_MODE, 1 } } },
  54         /* Tent */
  55         { KE_SW, 0x04, { .sw = { SW_TABLET_MODE, 1 } } },
  56         { KE_END },
  57 };
  58
  59 static void lenovo_ymc_notify(struct wmi_device *wdev, union acpi_object *data)
  60 {
  61         struct lenovo_ymc_private *priv = dev_get_drvdata(&wdev->dev);
  62         u32 input_val = 0;
  63         struct acpi_buffer input = { sizeof(input_val), &input_val };
  64         struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
  65         union acpi_object *obj;
  66         acpi_status status;
  67         int code;
  68
  69         status = wmi_evaluate_method(LENOVO_YMC_QUERY_GUID,
  70                                 LENOVO_YMC_QUERY_INSTANCE,
  71                                 LENOVO_YMC_QUERY_METHOD,
  72                                 &input, &output);
  73
  74         if (ACPI_FAILURE(status)) {
  75                 dev_warn(&wdev->dev,
  76                         "Failed to evaluate query method: %s\n",
  77                         acpi_format_exception(status));
  78                 return;
  79         }
  80
  81         obj = output.pointer;
  82
  83         if (obj->type != ACPI_TYPE_INTEGER) {
  84                 dev_warn(&wdev->dev,
  85                         "WMI event data is not an integer\n");
  86                 goto free_obj;
  87         }
  88         code = obj->integer.value;
  89
  90         if (!sparse_keymap_report_event(priv->input_dev, code, 1, true))
  91                 dev_warn(&wdev->dev, "Unknown key %d pressed\n", code);
  92
  93 free_obj:
  94         kfree(obj);
  95         ideapad_laptop_call_notifier(IDEAPAD_LAPTOP_YMC_EVENT, &code);
  96 }
  97
  98 static int lenovo_ymc_probe(struct wmi_device *wdev, const void *ctx)
  99 {
 100         struct lenovo_ymc_private *priv;
 101         struct input_dev *input_dev;
 102         int err;
 103
 104         if (!dmi_check_system(allowed_chasis_types_dmi_table)) {
 105                 if (force)
 106                         dev_info(&wdev->dev, "Force loading Lenovo YMC support\n");
 107                 else
 108                         return -ENODEV;
 109         }
 110
 111         priv = devm_kzalloc(&wdev->dev, sizeof(*priv), GFP_KERNEL);
 112         if (!priv)
 113                 return -ENOMEM;
 114
 115         input_dev = devm_input_allocate_device(&wdev->dev);
 116         if (!input_dev)
 117                 return -ENOMEM;
 118
 119         input_dev->name = "Lenovo Yoga Tablet Mode Control switch";
 120         input_dev->phys = LENOVO_YMC_EVENT_GUID "/input0";
 121         input_dev->id.bustype = BUS_HOST;
 122         input_dev->dev.parent = &wdev->dev;
 123         err = sparse_keymap_setup(input_dev, lenovo_ymc_keymap, NULL);
 124         if (err) {
 125                 dev_err(&wdev->dev,
 126                         "Could not set up input device keymap: %d\n", err);
 127                 return err;
 128         }
 129
 130         err = input_register_device(input_dev);
 131         if (err) {
 132                 dev_err(&wdev->dev,
 133                         "Could not register input device: %d\n", err);
 134                 return err;
 135         }
 136
 137         priv->input_dev = input_dev;
 138         dev_set_drvdata(&wdev->dev, priv);
 139
 140         /* Report the state for the first time on probe */
 141         lenovo_ymc_notify(wdev, NULL);
 142         return 0;
 143 }
 144
 145 static const struct wmi_device_id lenovo_ymc_wmi_id_table[] = {
 146         { .guid_string = LENOVO_YMC_EVENT_GUID },
 147         { }
 148 };
 149 MODULE_DEVICE_TABLE(wmi, lenovo_ymc_wmi_id_table);
 150
 151 static struct wmi_driver lenovo_ymc_driver = {
 152         .driver = {
 153                 .name = "lenovo-ymc",
 154         },
 155         .id_table = lenovo_ymc_wmi_id_table,
 156         .probe = lenovo_ymc_probe,
 157         .notify = lenovo_ymc_notify,
 158 };
 159
 160 module_wmi_driver(lenovo_ymc_driver);
 161
 162 MODULE_AUTHOR("Gergo Koteles <soyer@irl.hu>");
 163 MODULE_DESCRIPTION("Lenovo Yoga Mode Control driver");
 164 MODULE_LICENSE("GPL");
 165 MODULE_IMPORT_NS("IDEAPAD_LAPTOP");